County agrees to start canal enhancement project

Multiple studies over multiple decades have pointed to residential canals as being one of the reasons for below average near-shore water quality in the Keys.

The Monroe Board of County Commissioners last Wednesday approved the first step in what promises to be a very long range plan to attempt to clean up those canals.

On a unanimous vote, the BOCC agreed to proceed with the first phase of an eventual residential canal enhancement program, authorizing AMEC Engineering to prioritize those canals needing the most help.

The first phase of the newest study will be to map the residential canals and sample those canals to determine areas where some type of treatment is most necessary.

The second phase will be to suggest various ways to enhance the water quality of those canals.

Some of the methods being bandied about in the early stages include the installation of weed gates, the installation of aerobic systems, backfilling canals and the installation of culverts to enhance water flow.

Several of those methods are already in use throughout the Keys, many installed by private property owners long concerned about the quality of the water in their back yards.

“The Department of Environmental Protection has declared canals here impaired water that empties into near-shore waters,” said County Commissioner George Neugent. “It’s something that eventually we will have to address.”

“And eventually there will be a level of work that must be done to address those issues,” he said.

Neugent said the process has already started with a demonstration project in Marathon, a project that he say will have to spread to the rest of the Keys to address those near-shore water quality issues.

Commissioner Kim Wigington said she is concerned that the county would be using public money to rehabilitate private property as many of the canals are owned to the mid-water mark by adjoining private property owners.

“Folks took certain responsibilities when they decided to purchase water front homes,” said Wigington. “I would hate to see the general taxpayer have to pay for what will eventually be a boon to private property owners.”

The end result, said Neugent, is to have a list of canals in order of priority to address potential near-shore water problems and to use that list to apply for state and federal grants to alleviate problems with residential canals emptying less-than-stellar water into cleaner receiver waters.

The problem began years ago when residential developers dredged fill from the canals to create more land for homes.

Port Pine Heights in Big Pine, for example, is largely built on fill dredged from the canals that criss-cross the subdivision.

Through the dredging process and that was then a lack of state and federal oversight, the canals became significantly deeper in many cases than the water into which they emptied. That caused issues with algae build-up and a lack of dissolved oxygen because the canals didn’t properly flush during the tide cycles. Stagnant water remained at the bottom of the canals.

And as more homes were built utilizing error-prone septic tanks and cesspits, waste leached into the canals through the porous rock that supports the island chain, with solids settling to the bottom and never properly flushing with the tides.

“We have already seen some rejuvenation of residential canals in areas where central wastewater systems have been installed,” said Neugent. “But that won’t go far enough and we need to address the aeration and flushing issues.”

How much that might cost is a complete unknown at this point, although former county staffers have put the price tag into the tens of millions of dollars to do the job effectively.

Because the Keys are part of the National marine Sanctuary and an Area of Critical State Concern for environmental issues, Neugent said he feels as though state and federal grant money can be obtained for large parts of the anticipated work

“It all goes with being good stewards of the environment,” said Neugent.

County officials expect the first phase, identification of canals and the miles affected, to be complete in months, with the second phase to follow soon after.